This is coolbert:
More on the American M1 helmet from that era of the Second World War, Korea, Vietnam.
More Q & A.
"The Better to See You With"
"In 'The High Price of Valor' there are photos of a submarine deck gun crew and others firing on a Japanese sampan. If I'm not mistaken, all those men are wearing their helmets backward. Was there a reason for this?"
YES, indeed there was!
"the front lip on the versatile American 'steel pot' offered protection from the sun and overhead shrapnel, but for naval gun crews - - when a clear view of the action from sea level to the air, from which and an enemy plane could appear, was paramount- - that was not necessarily an asset. Naval gunnery personnel on large vessels had specialized helmets, but for those on smaller vessels . . . it was common to turn the helmet backward to expand the vista"
Even my own experience  during the fifth week of basic training for qualification with the M14 rifle it was mandated that all personnel wear the HELMET BACKWARDS. So as to give you better vision and an unobstructed view of the field of fire..
All the better to see you with my dear!!
And now you know the rest of the story and once more also thanks to WW2 magazine.